Wednesday, 17 November 2004

Response of the crucifer flea beetle to hormone-related mutations in Arabidopsis thaliana

Margaret Gruber,, Jennifer Holowachuk,, Jennifer Kambeitz,, Juliana Soroka,, and Dwayne Hegedus, Saskatoon Research Centre, Agriculture and Agri-Food Canada, 107 Science Crescent, Saskatoon, SK, Canada

The crucifer flea beetle (Phyllotreta cruciferae) is a chronic pest of North American canola and Brassica vegetable crops. Flea beetles can also feed on Arabidopsis thaliani, a model plant species which has a wealth of genomics resources and which has a genome that is co-linear with the Brassica genome. Several approaches have suggested that specific plant hormones mediate the response of plant species to insect feeding. These factors led us to assess hormone-related Arabidopsis mutations for crucifer flea beetle feeding using a field-based seedling bioassay and five-point rating system. Cytokinin-insensitive ethylene-over-producing (CIN4,5) lines and ethylene-insensitive (EIN2,3,5,7) lines were more resistant to flea beetle feeding than a Columbia parent line. In contrast, a cytokinin-insensitive ethylene-defective (CIN1) line and an ethylene constitutive-triple-response (CTR1) line were more susceptible to flea beetle feeding. Abscisic-acid-insensitive (ABI4,5) lines, a line defective in the last step of absiscic acid biosynthesis (ABA3), and three lines mutated in an auxin-responsive transcription factor (called ETTIN or ARF3) were also more susceptible. These data are enabling us to dissect hormone-related response pathways that affect flea beetle feeding, and may point us to hormone-related ESTs that are useful in developing flea beetle-resistant canola plants.

Species 1: Coleoptera Chrysomelidae Phyllotreta cruciferae (crucifer flea beetle)
Keywords: Arabidopsis

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